Determination of penicillamine in pharmaceutical formulations using kinetic method with spectrofhotometric detector : master thesis

Korištenjem kinetičke spektrofotometrije razvijena je i vrednovana nova metoda određivanja penicilamina (PEN) u farmaceutskim pripravcima. Metoda se temelji na redoks reakciji između bis batokuproin bakrov(II) kompleksa i penicilamina pri čemu nastaje stabilan kompleks narančaste boje, bis batokuproin bakrov(I) kompleks. Nastali kompleks postiže apsorpcijski maksimum pri valnoj duljini od 483 nm. Optimizirani su parametri koji utječu na kemijsku reakciju. Kod izrade krivulja umjeravanja korištene su metoda početne brzine i metoda odabranog vremena. Krivulja umjeravanja metodom početne brzine linearna je u području koncentracija od 6,0 × 10 −7 do 4,0 × 10 −5 mol L −1 , s granicom dokazivanja od 1,8 × 10 −7 mol L –1 . Nagib krivulje umjeravanja dobiven metodom početne brzine (1,0448) potvrđuje reakciju pseudoprvog reda. Krivulja umjeravanja metodom odabranog vremena (prva minuta) linearna je u području koncentracija od 2,0 × 10 −7 do 4,0 × 10 −5 mol L −1 , s granicom dokazivanja od 6,0 × 10 −8 mol L –1 . Predložena metoda uspješno je primijenjena kod određivanja penicilamina u komercijalnim farmaceutskim pripravcima što je uspoređeno s rezultatima dobivenim preporučenom metodom po farmakopeji.Kinetic spectrophotometry was employed for development and validation of new method for determination of penicillamine (PEN) in pharmaceutical formulation. The method is based on a redox reaction in which the reduction of copper(II) – neocuproine by penicillamine occurs, with formation of stable coloured, yellow-orange complex of copper(I) – neocuproine. The resulting complex exhibits an absorption maximum at λ = 483 nm. The parameters of chemical reaction have been optimized. The initial rate and fixed time methods were utilized for constructing the calibration graphs. The graph for initial rate method was linear in concentration range from 6,0 × 10 −7 do 4,0 × 10 −5 mol L −1 with the limit of detection 1,8 × 10 −7 mol L –1 . The slope of the initial method calibration curve (1.0448) confirmed the first order reaction. The graph for fixed time method (1 min) was linear in concentration range from 2,0 × 10 −7 do 4,0 × 10 −5 mol L −1 with the limit of detection 6,0 × 10 −8 mol L –1 . No interferences were observed from the excipients that are commonly present in the pharmaceutical formulations. The proposed method was successfully applied for the determination of PEN in its commercial pharmaceutical formulation, which is compared to the results obtained by the recommended method in Pharmacopoeia